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