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