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