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)(25,26,30,34)(27,35,38,39)(28,33,29,32)(31,36,40,37)(3,4)(6,8)(9,10)(11,16)(12,15)(13,17)(14,18)(19,23)(20,22)(21,24)(25,27)(26,31)(28,36)(29,37)(30,38)(32,39)(33,35)(34,40) involution — undirected(1,2,5,7)(3,6,4,8)(9,11,14,21)(10,16,18,24)(12,20,13,19)(15,22,17,23)(26,32)(28,29)(31,39)(33,34)(35,40)(36,37)(1,3,5,4)(2,6,7,8)(9,12,14,13)(10,17,18,15)(11,19,21,20)(16,22,24,23)(25,28,30,29)(26,32,34,33)(27,36,38,37)(31,39,40,35)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.