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