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