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