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