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