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