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