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