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