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