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