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