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