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