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