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