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