One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,8)(4,7)(5,6)(9,10,14,17)(11,15,18,13)(12,16,20,23)(19,21,24,22)(26,31)(27,33)(32,39)(34,36)(3,4)(7,8)(9,11)(10,15)(12,19)(13,17)(14,18)(16,21)(20,24)(22,23)(25,26)(27,29)(28,32)(30,31)(33,38)(34,37)(35,39)(36,40) involution — undirected(1,3)(2,7)(4,6)(5,8)(11,18)(12,20)(13,15)(16,23)(27,33)(28,35)(29,38)(32,39) involution — undirected(3,4)(7,8)(9,12)(10,16)(11,19)(13,22)(14,20)(15,21)(17,23)(18,24)(25,27)(26,29)(28,36)(30,33)(31,38)(32,40)(34,35)(37,39) involution — undirected(1,4,6,3)(2,7,5,8)(9,13,14,15)(10,11,17,18)(12,21,20,22)(16,24,23,19)(25,28)(26,32)(27,34)(29,37)(30,35)(31,39)(33,36)(38,40)(1,5,6,2)(3,7,4,8)(9,11)(10,15)(12,19)(13,17)(14,18)(16,21)(20,24)(22,23)(25,29)(26,27)(28,37)(30,38)(31,33)(32,34)(35,40)(36,39)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.