One vertex per element, one color per generator, with an edge from x to x·s.
(9,10,14,19)(11,15,21,16)(12,17,22,23)(13,20,24,18)(25,26)(27,33)(28,36)(29,34)(30,31)(32,38)(35,37)(39,40)(1,2)(3,6)(4,7)(5,8)(9,11)(10,15)(12,18)(13,17)(14,21)(16,19)(20,22)(23,24)(26,31)(27,34)(32,36)(35,40) involution — undirected(1,3)(2,5)(4,8)(6,7)(9,11,14,21)(10,16,19,15)(12,20,22,18)(13,23,24,17)(25,27)(26,29)(28,35)(30,34)(31,33)(32,37)(36,39)(38,40)(3,8)(5,6)(9,11)(10,15)(12,18)(13,17)(14,21)(16,19)(20,22)(23,24)(25,28,30,38)(26,32,31,36)(27,35,34,40)(29,37,33,39)(1,3)(2,6)(4,8)(5,7)(9,12)(10,17)(11,20)(13,16)(14,22)(15,24)(18,21)(19,23)(25,26)(27,29)(28,32)(30,31)(33,34)(35,37)(36,38)(39,40) involution — undirected(1,2)(3,6)(4,7)(5,8)(9,13,14,24)(10,18,19,20)(11,17,21,23)(12,16,22,15)(25,29)(26,27)(28,37)(30,33)(31,34)(32,35)(36,40)(38,39)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.