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)(11,15)(12,16)(13,22)(14,18)(17,23)(19,20)(21,24)(25,26)(27,28)(29,32)(30,38)(31,34)(33,40)(35,37)(36,39)(2,3)(6,7)(9,11)(10,15)(12,13)(14,19)(16,22)(17,24)(18,20)(21,23)(25,27,31,32)(26,28,34,29)(30,39,40,35)(33,37,38,36)(1,3,5,2)(4,7,8,6)(11,19)(12,21)(15,20)(16,24)(25,28,31,29)(26,32,34,27)(30,36,40,37)(33,39,38,35)(1,4,5,8)(2,6,3,7)(9,12,14,21)(10,16,18,24)(11,13,19,23)(15,22,20,17)(25,26)(27,28)(29,32)(30,33)(31,34)(35,36)(37,39)(38,40)(9,13)(10,17)(11,12)(14,23)(15,24)(16,20)(18,22)(19,21)(25,29,31,28)(26,27,34,32)(30,37,40,36)(33,35,38,39)(9,10)(11,20)(12,16)(13,17)(14,18)(15,19)(21,24)(22,23)(25,30,31,40)(26,33,34,38)(27,35,32,39)(28,36,29,37)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.