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