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