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