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