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