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