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