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