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