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