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