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