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