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