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