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