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