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