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