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