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